The invention relates to an electrical installation comprising an enclosure wherein there are arranged conductors and, possibly, electrical apparatuses such as current breaking, measuring, switching or electrical transformation apparatuses. More particularly, but in non-exclusive manner, the invention relates to a high-voltage electrical installation with gas insulation. In the whole of the text, the term “high voltage” will be taken in its broadest sense as also including what is known in certain countries as the field of “medium voltage”.